A difficult obstacle associated with the exploration and production of oil and gas is management of significant ocean currents. These currents can produce vortex-induced vibration (VIV) and/or large deflections of tubulars associated with drilling and production. VIV can cause substantial fatigue damage to the tubular or cause suspension of drilling due to increased deflections.
Helical strakes can be installed over the tubular to mitigate VIV. Helical strakes reduce the correlation of vortex shedding and thereby reduce the synchronization of vortex shedding forces required to produce large vibrations of a long slender tubular.
Typically helical strakes are bonded to the tubular or attached to the tubular so that the strake body is adjacent to the tubular surface. This causes a problem with many cathodic protection systems, which require the circulation of fluid adjacent to the tubular in order for the cathodic protection systems to function properly. Since the helical strake bodies are typically wrapped sufficiently tight against the tubular surface to restrict slipping on a vertical tubular, the cathodic protection systems may be compromised. In addition, the presence of helical strake body adjacent to the tubular surface can also produce unwanted thermal insulation.